Livestock such as cattle can be managed with individually-set individual identification numbers. For example, the cattle is managed with ear-tags attached to the ears, in which the individual identification numbers are described (see Non-Patent Literature 1). Further, in recent years, due to downsizing of communication modules, there is also known an ear-tag with which individual identification can be wirelessly performed with respect to a transmitter attached to the body of a livestock animal (e.g., see Patent Literature 1).
On the other hand, in management only with the ear-tags, individual identification sometimes becomes difficult if the ear-tags are detached.